About the Sentence Counter
Long sentences are one of the most common reasons prose feels heavy. A single 50-word sentence can be fine. A paragraph full of them tires the reader, especially on a phone or a Kindle screen. This tool counts your sentences, works out the average length, and lists every sentence over your chosen limit so you know exactly where to look.
The default limit is 25 words, a widely used readability guide for general fiction and nonfiction. Lower it for children's books or punchy marketing copy such as a book description, or raise it for literary or academic writing where longer sentences are expected.
Variety matters as much as averages: a mix of short and long sentences creates rhythm. Use the shortest and longest figures to check that range. For paragraph-level pacing, try the Paragraph Counter. For a quick total, the Word Counter is faster.
How It Works
Text is split into sentences at full stops, question marks, exclamation marks and ellipses when the next word starts with a capital letter or a number. Closing quotation marks and brackets stay with their sentence.
Words are counted in each sentence. The average is the total word count divided by the number of sentences.
Sentences with more words than your limit are listed with their position in the text and their word count.
Formula
- Average sentence length
- Average = Total words ÷ Number of sentences
Example
Checking the built-in sample passage with a 25-word limit
- Press Try sample text and keep the limit at 25 words.
- Sentences: 7. Average length: 18.7 words.
- Longest sentence: sentence 4, at 53 words.
- Sentences over 25 words: sentence 4 (53 words) and sentence 7 (31 words).
Two of the seven sentences run long, and the 53-word sentence is the obvious one to split.
Important Notes
- Abbreviations such as "Mr." or "e.g." followed by a capital letter can split a sentence early.
- A sentence that ends without punctuation runs into the next one, so headings without full stops may join the following sentence.
- Dialogue tags after a question or exclamation, such as "Why?" she asked, are usually kept together because the next word is lower case.
- Your text is processed in your browser and never uploaded.
Frequently Asked Questions
What is a good average sentence length?
For most commercial fiction and general nonfiction, an average of 15 to 20 words reads comfortably. Children's books and thrillers often sit lower. Literary fiction often runs higher.
Should every sentence be under 25 words?
No. The limit is a flag, not a rule. Long sentences are useful for building tension or description. The list simply shows you where they are so you can decide.
Why does my count differ from another tool?
Sentence splitting depends on rules for abbreviations, quotes and ellipses. This tool needs a capital letter or number after the punctuation, which avoids most false splits but not all of them.
Can I check my book description?
Yes. Short sentences help a description scan well on the Amazon product page. Try a limit of 15 to 20 words for descriptions.
Does it work for languages other than English?
It works for languages that use capital letters and the same end punctuation. Languages without capitals, or with different sentence marks, may not split correctly.
Related KDP Tools
- Paragraph CounterCount paragraphs and see average and longest paragraph length.
- Word CounterA fast, private word counter with top-word frequency.
- Character CounterCount characters with and without spaces, plus bytes and limits.
- Book Deadline CalculatorWork out daily word targets or your finish date from your writing pace.
- Percentage CalculatorPercent of a number, percentage change and what-percent-of calculations.
- Margin CalculatorCalculate profit margin and markup from cost and price, or price from target margin.